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Re: [TowerTalk] Hardline ?

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Hardline ?
From: Pete Smith <n4zr@contesting.com>
Date: Sun, 19 Apr 2009 06:22:31 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Many years ago, W4AN (SK) came up with a way to use a common plumbing 
adapter - I think it was 1/2" water pipe to 1/2 inch copper tubing - 
to put an Amphenol UHF barrel connector on the end of CATV hardline. 
The advantage of his approach was that it required no machining, only 
a little silver soldering and hacksaw work on the barrel.  You should 
be able to google for this - I remember it was on the cq-contest and 
towertalk reflectors several times, so their searchable archives 
would be another place to look.

Your RG-214 is 50-ohm cable, while the CATV stuff is presumably 
75-ohm.  Unless you cut the hardline (plus a pigtail of RG-11 for 
ease in adjusting the length) to a multiple of 1/2 wavelength at the 
lowest frequency you intend to use, it will act as a transformer.  If 
it is an odd multiple of 1/4 wavelength long (the worst case) and you 
attach it to a perfect 50-ohm load, the impedance at the shack end 
will be around 110 ohms.  If the load is reactive, the effect is worse.

I used the 1/2-wave solution for about 10 years (I think it was 
actually 1.5 wavelengths at 160 meters) and it worked fine.

73, Pete

At 10:03 PM 4/18/2009, Roger (K8RI) wrote:
>Here's just one of the many ways to put connectors on them.
>http://www.rogerhalstead.com/ham_files/conn.htm
>
>73
>
>Roger (K8RI)
>
>Steve Parker wrote:
> > Hello, a eham member suggested posting my question here. I have 
> acquired my 1st section of 3/4 in hardline from my local cable 
> company and need to splice it to my RG-214. I am still pretty new 
> to the hobby and have no idea the best way to go about this. All 
> help is greatly appreciated, and any links with detailed photos, 
> and parts list are as well.
> >
> > Thanks
> >
> > 73
> >
> >
> > Steve Parker
> > NZ4Z  /  USA
> >
> > www.nz4z.myqsx.net
> >
> >
> >
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